Conventionally, a linear motor utilized for a machine tool or precision feeding of a semiconductor manufacturing system or the like has a structure such as that shown in FIG. 4.
FIG. 4 is a front cross-sectional view showing the entire configuration of a common linear motor, which will be described by means of taking as an example a linear motor having a through-flux-type structure. Reference numeral 1 designates a linear motor; 2 designates an armature which permits penetration of a magnetic flux; 3 designates an armature core formed by stacking flat rolled magnetic steel sheets and strips one on top of the other; 4 designates an armature winding coiled around the armature core 3; and 5 designates smoothing magnetic field magnets which are disposed on both longitudinal sides of the armature core 3 so as to oppose each other at right angles by way of a gap and which are formed from permanent magnets. Reference numeral 6 designates smoothing yokes which have the magnets 5 affixed thereon and permit penetration of a magnetic field; 7 designates a table disposed on an upper surface of the armature 2; 8 designates linear guides; 8a designates guide rails; 8b designates sliders; 9 designates an armature mount plate; 9a designates female screw sections; 22, 23 designate fastening bolts; and 24 designates a fixed bed.
In such a linear motor 1, the magnetic-field-side smoothing yokes 6 are fixed on the fixed bed 24, and the armatures 2 are fastened by means of screwing the fastening bolts 22 into the female screw sections 9a of the armature mount plate 9 by way of through holes 3a of the armature core 3. The table 7 is fastened by means of screwing the fastening bolts 23 into female screw sections 9b formed in the armature mount plate 9, by way of through holes 7a. The linear motor 1 is further supported by the linear guides 8 which are each formed from the guide rail 8a and the slider 8b. The armature 2 carrying the table 7 generates thrust in the direction of a line of the permanent magnets 5, thereby enabling smooth linear movement.
Particularly, in relation to the structure of the armature which is required to increase the stroke of the movable member according to an application, an armature shown in FIGS. 5 and 6 is put forward as the armature of such a linear motor (described in, e.g., JP-A-2000-278929).
FIG. 5 shows the armature of the linear motor showing a first background-art technique, wherein FIG. 5A is a side cross-sectional view of the armature, and FIG. 5B is a plan view of the armature when viewed from the bottom thereof. The drawings show an example wherein the number of armature blocks is three and the number of teeth per armature block is nine.
The armature core 3 includes a first armature block 10, a second armature block 11, and a third armature block 12, and spacers 14 are provided between the armature blocks, thereby maintaining gaps. The armature blocks 10 to 12 and the spacers 14 are arranged in the direction of thrust of the linear motor and fixed by the armature mount plate 9. Each of block cores 31 constituting the respective armature blocks 10 to 12 has teeth sections 31a arranged at equal pitches and are sequentially coupled together by way of engagement sections 31b. 
During coil wire processing of the armature 2, an armature winding 4 formed from an U-phase coil, a V-phase coil, and a W-phase coil is housed in each of the teeth 31a of the respective armature blocks 10 to 12 such that a lead wire 13 of each armature winding 4 is led from the bottom of the armature block 31 to the direction of thrust of the linear motor. Moreover, the surroundings of the armature block and the bottom of the same where the lead wire 13 is provided are fixed with resin mold 17. Reference numeral 18 designates a terminal box; and 18a designates a connector terminal. The lead wires 13 of the respective armature windings are bundled into the terminal box 18 and connected to the connector terminal 18a. 
The coil wire processing of the other coils of the armature 2 is performed as shown in FIG. 6. FIG. 6 shows an armature of a linear motor showing a second background-art technique, wherein FIG. 6A is a side cross-sectional view of the armature, and FIG. 6B is a plan view of the armature when viewed from the bottom. The drawings show an example wherein the number of armature blocks is three and the number of teeth per armature block is nine.
In FIG. 6, reference numeral 15 designates a first lead wire through passage; and 20 designates a second lead wire through passage. Formed in each of the spacers 14 provided between the armature blocks 10 to 12 is the first lead wire through passage 15 having a bore section oriented in the longitudinal direction (i.e., the direction at right angles to the armature mount plate 9) of the spacer. The second lead wire through passage 20 is formed so as to communicate with the first lead wire through passage 15 in the longitudinal direction of the armature mount plate 9. A trench having a depth which enables accommodation of the lead wire 13 is formed in the second lead wire through passage 20 from the surface of the armature mount plate 9 toward the inside thereof.
However, the background-art techniques have the following problems.    (1) During the lead wire processing of the armature winging 4 shown in FIG. 4, the lead wire 13 of each armature winding 4 is led from the bottom sections of the armature blocks 10 to 12 to the direction of thrust of the linear motor, and the lead wires are collectively extracted to the terminal box. Since the number of block cores 31 and the number of armature blocks are increased, the lead wires 13 of respective phase coils in the bottom sections of the armature blocks become larger in number and bulky, which is responsible for deterioration of the efficiency of operation for assembling the armature block.    (2) During the lead wire processing of the armature coil 4 shown in FIG. 5, the volume of lead wires is reduced by effective utilization of the spacers 14. However, the lead wires are mounted, in a spreading manner, at a plurality of locations, such as the spacers, the armature mount plates, and the bottom sections of the armature blocks. Hence, this configuration also encounters difficulty in rendering efficient the operation for assembling the armature block.    (3) Moreover, when the related-art techniques are applied to a case where the present invention is applied to a plurality of feed rods, as an example to which the linear motor is applied, the respective feed rods require a plurality of linear motors having different thrust specifications. The respective motors require armatures of different shapes and dimensions. Therefore, this case is disadvantageous in terms of (1) an increase in costs incurred in development and investment of the linear motors used in one machine tool and (2) a necessity for replacing the entire armature block including armatures with a new armature block when imperfections have arisen in a part of the armature block.
The present invention is conceived to solve the foregoing problems and is aimed at providing an armature of a linear motor and a linear motor, which facilitate lead wire processing of armature windings, render efficient an operation for assembling an armature block, and enable an attempt to increase the thrust of a motor in accordance with an increase in the stroke of a movable member.